Should You Take a Breathalyzer or Blood Test in Arizona?

One of the most common questions Arizona drivers ask is whether they should “blow” or submit to a blood test during a DUI stop. It is a great question, and the answer is not the same for every test. Knowing the difference between the voluntary roadside tests and the official post-arrest test can protect both your license and your defense.

The Short Answer: There Are Two Different Tests

A DUI stop actually involves two separate categories of testing, and they have very different rules:

• Roadside tests (voluntary): the field sobriety tests and the small handheld portable breath test (PBT) the officer offers before an arrest. These are optional, and you can decline them with no automatic penalty.
• The official chemical test (implied consent): the evidentiary breath or blood test given after you are arrested. This one is covered by Arizona’s implied-consent law, and refusing it carries real consequences.

Confusing the two is where people get hurt.

Field Sobriety Tests and the Portable Breath Test Are Voluntary

Before an arrest, the officer will usually ask you to perform field sobriety tests, the eye test, the walk-and-turn, and the one-leg stand, and to blow into a small handheld device at the roadside. In Arizona, these are voluntary. You can politely decline all of them, and there is no automatic license penalty for doing so, because they are not the “chemical test” covered by implied consent.

These roadside tests are designed to build probable cause to arrest you. Politely declining them, while staying calm and respectful, avoids handing the officer that evidence.

The Official Test and Arizona’s Implied-Consent Law (A.R.S. 28-1321)

Once you are arrested for DUI, a different rule applies. Under A.R.S. 28-1321, by driving in Arizona you have “impliedly consented” to a breath, blood, or urine test if you are lawfully arrested for DUI. This is the official, evidentiary test, and it is not the same as the roadside portable device.

If you refuse this test, two things happen: your license is suspended, and the police get your blood anyway.

What Happens If You Refuse in Arizona

• Automatic license suspension. A first refusal triggers a 12-month suspension of your driving privilege; a second refusal within 84 months is a 24-month suspension. This is separate from the criminal case.
• Police get a warrant. Officers routinely obtain a quick telephonic search warrant and draw your blood by force if necessary, so refusing rarely keeps the evidence out.
• You can still be charged and convicted. The State can use your refusal against you in court and can still prosecute the DUI.

For most people, refusing the official post-arrest test means losing your license for a year and the blood being taken anyway, the worst of both worlds.

Breath Test vs. Blood Test

The official test may be breath or blood. Breath tests rely on a machine (the Intoxilyzer 8000) that must be calibrated and maintained, and are prone to error. Blood tests are treated as more precise but depend on a proper draw, storage, and an unbroken chain of custody. Both are challengeable, which is why a “failed” test is far from the end of your case.

Do Not Blow Right After Mouthwash, Brushing, or Burping

A frequently searched question is how long to wait before a breath test. Residual “mouth alcohol” from mouthwash, breath spray, dental work, burping, or acid reflux can spike a breath reading far above your true level. Arizona requires officers to observe you for 15 minutes before the official breath test for exactly this reason, and when they do not, the reading can be challenged. Certain medical conditions and even GLP-1 drugs like Ozempic can also skew a breath test.

You Have Only 15 Days to Save Your License

Whether you refused or submitted, a DUI arrest starts a separate clock at the MVD. You have just 15 days from your arrest to request an MVD hearing, or your license is automatically suspended. This deadline is easy to miss, so it is one of the first things a DUI lawyer handles.

We Can Challenge the Test Either Way

Whether you took the test or refused it, the result is not the end of your case. We attack calibration and maintenance records, the 15-minute observation, mouth alcohol, the blood draw and chain of custody, and the rising-BAC timeline, and we fight the license suspension at the MVD. A test result, or a refusal, is just the starting point of the defense.